The invention relates to a motor arrangement comprising at least three electric motors, each comprising a stator having the form of a hollow, tapering, and substantially rotationally symmetrical body and a rotor, the axes of rotation of the motors being substantially arranged in one and the same plane and being so mutually spaced angularly that adjacent axes of rotation intersect each other in a common intersectional point at angles which are substantially equal to 360.degree. divided by the number of comprised motors. The invention also relates to the use of such motor arrangements as rudder motors in missiles.
Arrangements of this type and comprising four conventional torque motors are previously known. By a conventional motor in this case is meant a motor having a cylindrical rotor and a stator adapted thereto. A motor arrangement consisting of four such conventional motors is relatively bulky because there is a relatively large space in the center of the motor arrangement which is not used. In some applications, for example as rudder motors in missiles etc., the motor arrangement occupies an inadvantageously large part of the space.
Torque motors of the kind set forth have a torque which is linearly dependent on the length of the rotor-stator unit and approximately related to the square of its diameter. In this connection a motor constant K.sub.M may be defined as: ##EQU1## where T.sub.p is the peak torque and P.sub.p peak power input at stall condition.
Electrical motors with a cone-shaped stator per se are previously known (see EP No. A1 0 010 685 FIGS. 13-14 with the corresponding text). However, there are no suggestions in this publication to make the motor exterior concial or to use such motors in a compact motor arrangement comprising more than one motor in a common plane and in an optimal way utilizes an available volume.